Wednesday, February 03, 2016

New and updated Earth Fissure maps released for Maricopa, Pinal, and Cochise counties

AZGS has released six revised and upated earth fissures in south-central and southeastern Arizona for parts of Maricopa, Pinal and Cochise Counties. A single new earth fissure map for just east of the Picacho Mountains in Pinal County was issued.

Updated earth fissure study area maps, include: Luke and Chandler Heights in Maricopa County; Picacho and Friendly Corners (3 map sheets) and Santa Rosa Wash in Pinal County; and North Sulphur Springs Valley and Dragoon Road study areas in Cochise County. 

The maps and digital data are available at the Natural Hazards of Arizona viewer. Individual fissure study area maps are online at the Arizona Geological Survey’s Online Document Repository. A Google Earth .kmz file is available for viewing the fissures on Google Earth. 

All new or revised earth fissure maps employ a base map displaying National Agriculture Imagery Program aerial photography and, when available, a local subsidence map, provided courtesy of the Arizona Department of Water Resources. 

A new fissure line category (yellow lines) portrays select fissures as confirmed that were otherwise not mapped by AZGS’ fissure mapping team. These include fissures mapped by reliable sources and those identified on multiple aerial photographs. Previously, if fissures could not be identified during field checks, the fissure was reported as unconfirmed.

Besides posing a threat to infrastructure, fissures are frequently used for illegal dumping of tires, appliances, construction debris, manure and other sundry items.  Because fissures extend downward towards the groundwater table, they represent a potential conduit for surface runoff to contaminate aquifer resources.

AZGS’s earth fissure mapping team will continue to monitor existing earth fissures and map new ones as they form.  AZGS geologists collaborate with hydrologists from the Arizona Dept. of Water Resources to better understand where and when fissures will occur, and with local environmental and geological engineers on ways to mitigate and minimize the impact of earth fissures.

[excerpted from the AZGS announcement]

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